Concept: Mixtures and Pure Substances
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Transcript of Concept: Mixtures and Pure Substances
Concept: Mixtures and Pure Substances
UEQ: How does the structure of matter influence its physical and chemical behavior?LEQ: How is matter classified?
Bell Work 09/19/2012
Write question and answer.
Can you chemically break down an atom? Why or why not?
Too much energy is required to break an atom down into its protons, neutrons, and electrons alone. It would require a nuclear reaction to do this.
UEQ: UEQ: How does the structure of matter influence its physical and chemical behavior?LEQ: How is matter classified?
Bell Work 10/05/2012
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Explain why is it easier to separate a heterogeneous mixture than a homogeneous mixture?
In a heterogeneous mixture, you can identify the components of the mixture
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How is matter classified?
Vocabulary Write word and definition.
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Heterogeneousmixture
Homogeneousmixture
SolutionSoluteSolventSuspensionColloid
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How is matter classified?
What are atoms? The smallest unit of an element
that maintains the chemical properties of that element
UEQ: How does the structure of matter influence its physical and chemical behavior?LEQ: How is matter classified?
What is matter? Anything with mass and volume
(or takes up space) Matter can be broken into two
categories Pure Substances (1st) Mixtures
UEQ: How does the structure of matter influence its physical and chemical behavior?LEQ: How is matter classified?
Pure Substances
Definite composition/uniform/unchanging
Pure substances can be broken down further into two more categories: elements and compounds
UEQ: How does the structure of matter influence its physical and chemical behavior?LEQ: How is matter classified?
Elements A substance that cannot be
separated or broken down into simpler substances by chemical means
Found on periodic table
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How is matter classified?
Compounds 2+ atoms chemically bound Must break bonds to get elemental form May form molecules
Water Carbon dioxide
Law of Definite Proportions The law that states that a chemical
compound always contains the same elements in exactly the same proportions by weight or mass
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How is matter classified?
Mixtures Contains 2+ kinds of matter
physically mixedCan be physically separated Broken down into 2 main groups
Homogeneous Heterogeneous
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can substances be identified as homogeneous or heterogeneous?
Homogeneous Mixtures Looks pure b/c evenly/uniformly mixed Also called a solution▪ Solid in liquid (salt water)▪ Gas in liquid▪ Solid in solid▪ Alloys-mixture of 2+ metals▪ Solid at room temperature
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can substances be identified as homogeneous or heterogeneous?
solutions▪ Solute – substance being dissolved (sugar)▪ Solvent – substance doing the dissolving
(water)
RULE OF THUMB!!! USUALLY YOU WILL HAVE MORE SOLVENT THAN SOLUTE!!!
What is solubility?▪ Amount of solute that can be dissolved▪ Concentration – high C – high solute/solvent,
low C – low solute/solvent
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can substances be identified as homogeneous or heterogeneous?
Heterogeneous Looks impure - Substances can be
identified Not uniform throughout b/c unevenly
mixed Examples: granite, wood, blood,
tossed salad Also called suspensions▪ Visible particles settle
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can substances be identified as homogeneous or heterogeneous?
Colloids Ex. Milk, fog, clay Look like a solution b/c particles do
not settle, but acts like a suspension b/c particles do not dissolve
How can you tell if it is a colloid?▪ Tyndall effect – scattering of light by
particles in a mixture
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can substances be identified as homogeneous or heterogeneous?
Solution
Colloid Suspension
Does it settle?
No No yes
Can it be filtered?
No No Yes
Does it scatter light?
No Yes Yes
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can substances be identified as homogeneous or heterogeneous?
Bell Work 10-08-2012
Write Question and AnswerHow can you tell a solution,
suspension, and colloid apart from one another? Differentiate between the 3.
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can substances be identified as homogeneous or heterogeneous?
Bell Work 09-21-2012Write Question and AnswerHow can you tell a solution, suspension, and colloid
apart from one another? Differentiate between the 3.Solution is a homogeneous mixture where particles are
uniform throughout and does not settle. Suspensions are heterogeneous mixtures that have particles that settle and it is not uniform throughout. Colloids fall in between solutions and suspensions in that it has particles that do not settle (like solutions); but, the particles do not dissolve (like in suspensions). You can also use the Tyndall effect to differentiate colloids from solutions because colloids will scatter the light.
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can the components of mixtures be separated?
Methods for separating mixtures Distillation Filtration Chromatography
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can the components of mixtures be separated?
Distillation Separating mixture by using differences in
boiling points Good for separating solutions How? Heat mixture to the b.p. of the substance
with the lowest b.p. This will create a vapor first. Collect and condense into a liquid in a separate container. Continue process if solution contains more than 2 substances.
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can the components of mixtures be separated?
Filtration Separating solid from liquid Use porous barrier to separate
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can the components of mixtures be separated?
Chromatography Separation technique that identifies
parts of a mixture by how fast compounds move across a material
Greatest attraction moves the fastest
UEQ: In dealing with matter, how are composition, structure, properties and energy related? LEQ: How can the components of mixtures be separated?
Write question and answer.
Explain how you could separate sand and salt.
You could first add water to the solid mixture to form salt water. Filter the salt water from the sand. This will leave sand in the filter and salt water in the container. Then, through distillation process, heat the salt water to the water’s boiling point so that you can collect and condense water vapor in separate container leaving only salt behind.